Question

How many vibrations are expected for PF5?

How many vibrations are expected for CH4?

How many vibrations are expected for PF3?

How many vibrations are expected for CH2O?

How many vibrations are expected for C2H6?

How many vibrations are expected for C2H5OH?

Answer 1

Normally

The degrees of vibrational modes for linear molecules can be calculated using the formula

3N−5

The degrees of freedom for nonlinear molecules can be calculated using the formula

3N−6, where, N is equal to the number of atoms within the molecule of interest.

for PF₅ the number of vibrations is 3X6 - 6 = 12 expected vibrations.

for CH₄ the number of vibrations is 3X5 - 6 = 9 expected vibrations.

for PF₃ the number of vibrations is 3X3 - 6 = 3 expected vibrations.

for CH₂Othe number of vibrations is 3X4 - 6 = 6 expected vibrations.

for C₂H₆ the number of vibrations is 3X8 - 6 = 18 expected vibrations.

for C₂H₅OH the number of vibrations is 3X9 - 6 = 21 expected vibrations.